Cross-linkable and/or cross-linked nanofiller compositions

ABSTRACT

The present invention relates to a cross-linkable and/or cross-linked nanofiller composition which comprises a cross-linkable and/or cross-linked ethylene (co)polymer and an intercalated nanofiller. The present invention also relates to processes for preparing the nanofiller composition, articles composed of the nanofiller composition and processes for preparing the articles.

FIELD OF THE INVENTION

The present invention relates to cross-linkable and/or cross-linkednanofiller compositions, processes for their preparation and articlescomposed of them, in particular cross-linkable and/or cross-linkednanofiller compositions containing cross-linkable and/or cross-linkedethylene (co)polymers such as polyethylene. These nanofillercompositions possess advantageous properties, more specifically,increased barrier properties, strength and higher heat distortiontemperatures which makes them useful in various applications includingmedical, automotive, electrical, construction and food applications.

BACKGROUND OF THE INVENTION

Thermoplastic polymers such as thermoplastic polypropylene have beenmixed with fillers such as clays or calcium carbonate to producecompositions which only show minimal improvement in mechanical andchemical properties with deterioration during processing.

When nanofillers were added to thermoplastic polymers such aspolypropylene in reduced amounts compared to standard fillers, someimprovements in properties were obtained such as increased mechanicalproperties including stress crack resistance and tensile strength,reduction in gas or liquid permeability and increases in crystallinemelting temperatures and flame retardancy e.g. reduced dripping in aflame. However, despite the addition of nanofillers, thermoplasticpolymers such as polypropylene are still thermoplastic and theirthermomechanical properties, tensile strength, resistance topermeability of gases or liquids, resistance to swelling and solventsand flame retardance at higher temperatures including in heat andsunshine is still reduced or limited. This is even more the case withpolyethylene which has much lower crystalline melting temperatures thanpolypropylene. Polyethylene is not traditionally treated in this waybecause of difficulties in achieving even limited improvements in theabove mentioned properties and in general these problems are consideredas not being solved with polyethylenes or ethylene copolymers.

The Stress Crack Resistance (SCR) and Environmental Stress CrackResistance (ESCR) of most thermoplastics at greater than ambienttemperatures such as in cars and cables can still be weakened,insufficient and can fail both in prolonged tests and use, in particularin the presence of chemicals, detergents, solvents, liquid fuels andoils.

The swellability and solubility of polyolefin thermoplastics e.g.ethylene polymers in certain solvents, fuels, oils, chemicals stronglyincreases at elevated temperatures up to unacceptable limits and theymay dissolve at elevated temperatures or when boiled or extracted insolvents at higher temperatures. Swellability means deterioration inproperties, softening, increase in dimensions, mechanical weakening tothe point of structural failure of the product made therefrom andultimately, in some cases to dissolution of the product.

The flame retardance e.g. of a thermoplastic polymer that has alreadyflame retardant additives, in case of a test or in a real fire, can bereduced or impaired by the dripping thermoplastic polymer in particularin the flame temperature ranges. Dripping can result in acceleration ofthe fire due to hot, molten, even burning drops of polymer falling onother parts of products under or in the vicinity of the burning polymer.

Thus, the improvements observed by the addition of nanofillers tothermoplastic polymers were not and are not sufficient to reach thehigher levels of performance required for increased safety levels of theproducts made therefrom both mechanically and thermo-mechanically, inparticular at higher temperatures or in other difficult conditions suchas exposure to chemicals, solvents, oils, fuels or short circuits. Theseproperties are very important for products such as fuel tanks forautomobiles, containers for solvents, chemicals, cables, aerial cables,power cables, foils and films. Furthermore, such compositions cannot beused to make heat shrinkable products for joints, sleeves, tubes, pipes,films and packaging.

A requirement accordingly exists for a nanofiller composition ornanocomposite containing thermoplastic polymers which has improvedproperties so that the products made from these compositions performwell, particularly at temperatures above ambient and/or in difficultenvironments such as exposure to chemicals, solvents, oils, fuels orshort circuits.

SUMMARY OF THE INVENTION

The present invention provides a cross-linkable and/or cross-linkednanofiller composition which comprises a cross-linkable and/orcross-linked ethylene (co)polymer and an intercalated nanofiller.

Preferably, the composition further comprises an organic silane graftedto the ethylene (co)polymer and/or intercalated into the nanofiller.

The present invention also provides a process for preparing across-linkable and/or cross-linked nanofiller composition whichcomprises either:

-   -   (a) mixing and exfoliating and/or delaminating in one step a        cross-linkable ethylene (co)polymer and an intercalated        nanofiller;    -   (b) mixing a cross-linkable ethylene (co)polymer with an        intercalated nanofiller; and    -   delaminating and/or exfoliating at least part of the nanofiller;        or    -   (c) delaminating and/or exfoliating at least part of an        intercalated nanofiller; and    -   mixing the delaminated and/or exfoliated intercalated nanofiller        with a cross-linkable ethylene (co) polymer.

In another aspect of the process, the ethylene (co)polymer and/ornanofiller are subjected to grafting either before, during or after themixing and delaminating and/or exfoliating step(s). The graftingpreferably involves treating the ethylene (co)polymer and/or nanofillerwith an organic silane which is then grafted onto the (co)polymer and/orintercalated into the nanofiller using a free radical initiator.

The present invention further provides an article which is wholly orpartly composed of the nanofiller composition defined above.

In a further aspect, the present invention provides a process forpreparing the article defined above which comprises either:

-   -   (a) forming or shaping the nanofiller composition defined above;    -   (b) combining at least one layer of the nanofiller composition        with at least one other layer;    -   (c) cross-linking the nanofiller composition defined above; or    -   (d) heating and stretching the nanofiller composition defined        above and cooling the stretched composition.

DETAILED DESCRIPTION OF THE INVENTION

Suitable ethylene (co)polymers include polyethylene and ethylene basedalkene or alphaolefin copolymers, for example, high density polyethylene(HDPE), medium density polyethylene (MDPE), linear low densitypolyethylene (LLDPE), low density polyethylene (LDPE), very low densitypolyethylene (VLDPE), and ultra low density polyethylene (ULDPE);ethylene hexene copolymers and ethylene octene copolymers; butylene(co)polymers such as polybutylene and polyisobutylene;ethylene-propylene copolymers (EPM); ethylene-propylene-dieneterpolymers (EPDM); ethylene-butylene copolymers (EBM) and terpolymers(EBDM); ethylene-vinylsilane (co)polymers; copolymers or terpolymers ofethylene with acrylic acid (EA) or ethylene with ethylene acrylate andacrylic acid (EAA) or methacrylic acid (EMA); and copolymers of ethylenewith ethylacrylate (EEA), butyl-acrylate (EBA) or vinyl acetate (EVA).It will be appreciated that these ethylene (co)polymers may also be inthe form of metallocene catalyst (co)polymers.

The ethylene (co)polymers or part of the ethylene (co)polymers may begrafted with compounds containing carboxylic acid or anhydride groupssuch as maleic anhydride or acid or fumaric anhydride or acid which mayfacilitate the exfoliation and/or delamination of the nanofiller.Examples of grafted ethylene (co)polymers suitable for use in thepresent invention include maleic anhydride (MAH) or maleic acid graftedcopolymers such as LDPE-MAH, HDPE-MAH, EP-MAH, EPR-MAH, PE-MAH orPP-MAH.

In a preferred embodiment, the ethylene (co)polymer contains or hasadded, for example, by grafting, polar groups, such as carboxylicgroups, for example, EEA or EA, maleic groups or ester groups, forexample, EVA, EEA or EBA.

The amount of (co)polymer with polar groups should preferably be atleast about 0.01% of the total (co)polymer, more preferably at leastabout 0.5%, most preferably at least about 5% and even more preferablyat least about 8%. In the case of premix masterbatches/concentrates ofnanofiller with (co)polymer(s) the amount of (co)polymer with polargroups is preferably at least about 10%, more preferably at least about15%, most preferably at least about 25% of the (co)polymer in themasterbatch/concentrate.

The ethylene content of the ethylene-propylene copolymers is preferablyabout 10 to about 99.9% by weight, more preferably about 40 to about99.9% by weight, most preferably about 75 to about 99.9% by weight.Unless stated otherwise, it will be understood that the term “% byweight” as used herein is based on the total weight of (co) polymer.

The vinyl acetate content of the ethylene-vinyl acetate copolymer (EVA)is preferably about 3 to about 80% by weight, more preferably about 9 toabout 70% by weight. The vinyl acetate content is preferably about 9 toabout 30% by weight for plastomeric EVA and about 38 to about 50% byweight for elastomeric EVA.

The ethylene (co)polymer may be an elastomer or a plastomer. Plastomersand elastomers can be characterised by means of specific gravity (S.G.)or density, for example, in the case of ethylene-alpha-olefin copolymersand other properties such as the differential scanning calorimetry (DSC)melting peak, Shore A hardness and elasticity modulus. Such propertieswill vary depending on the type of ethylene (co)polymer and its methodof manufacture and the amount of (co)monomer present. By way of example,EVA with up to about 28% VA is considered a plastomer and with aboveabout 38% being considered an elastomer. However, generally plastomersare plastomeric and elastomers are elastomeric or thermoplasticelastomeric and flexible.

Preferably, for plastomeric cross-linkable compositions, at least about40% to about 50% by weight, more preferably at least about 60% by weightis a plastomer with the balance being an elastomer. Examples ofplastomers include polyethylene such as HDPE, MDPE, LDPE, LLDPE orVLDPE; EVA with up to about 30% vinyl acetate; EPM with up to about 25%propylene; and ethylene octene copolymers with a S.G. of at least about0.887. The elastomers include ethylene octene copolymers with a S.G. ofup to about 0.886; an ethylene hexene copolymer; ULDPE; ethylenepropylene copolymers such as terpolymers with propylene comonomers ofgreater than about 30%; ethylene vinyl acetate copolymers with greaterthan about 38% vinyl acetate; EPDM; EPM; and EPR. Preferably, forplastic-elastomeric or elastomeric cross-linkable compositions, theelastomeric component will be at least about 40%, preferably about 50%,more preferably at least about 60% by weight of the total composition.The most preferred embodiment of this invention is a thermoplasticcross-linkable composition with at least about 40% plastomeric compoundby weight of the total composition.

The term “cross-linkable and/or cross-linked” is used herein in itsbroadest sense and refers to the ethylene (co)polymer and/or acomposition based on it being cross-linked or at least capable of beingcross-linked at a later stage or of being made cross-linkable. It willbe understood that at least one ethylene (co)polymer in the compositionmay be cross-linkable and/or cross-linked and such a (co)polymerpreferably forms at least about 30%, more preferably about 50%, mostpreferably at least about 70% by weight of the total (co)polymercomponent.

The term “nanofiller” is used herein in its broadest sense and refers tofillers having a particle size in the nanometre (nm) range, in the orderof size of less than about 500 nm. The thickness of the particles isapproximately in the order of about 1 nm to about 100 nm and thediameter or length or width can be up to about 500 nm. The ratio betweenthickness and length or width of the particles is called “aspect ratio”and it is preferred to have or to achieve a high aspect ratio. Theparticles have a platelet like structure. A nanofiller is capable ofbeing separated by intercalation, delamination and or exfoliation intosmaller size groups or layers of less than 100 nanometres thickness,into particles or layers with 1 to no more 5 platelets, preferably intoa high proportion of single platelets. When the nanofillers areexfoliated, the thickness of their platelets is reduced to about 1 toabout 3 nm. The nanofiller may be present in an amount of about 15 toabout 40%, preferably about 15 to about 30% of themasterbatch/concentrate.

The term “intercalated” or “intercalation” is used herein in itsbroadest sense and refers to a platelet-like or layered structure. Thelayers of the nanofiller which are generally composed of silicate aretreated chemically by removing some cations from between the layers andintercalated with ionic or polar substances including quaternaryammonium salts, such as, optionally substituted long chain hydrocarbonquaternary ammonium salts, for example, benzyl or alkyl substituted longchain hydrocarbon quaternary ammonium salts, alkyl substituted tallow orhydrogenated tallow quaternary ammonium salts; or bis-hydroxyethylquaternary ammonium salts. Suitable counter anions for the quaternaryammonium cations include halides such as chloride or methyl sulphate.

The intercalated nanofiller may be an intercalated mineral nanofiller orclay which is either synthetic or natural such as, montmorillonite,bentonite, smectite and phyllosilicate which can be or have beenintercalated by organic modification with an organic intercalatentselected from the ionic or polar compounds described above and may besold under the trade names Cloisite (Southern Clay Products), Nanofil(Sudchemie), Tixogel(Sudchemie) and Kunipia.

The organic intercalant may be present in an amount up to about 40% byweight of the nanofiller. The weights in the description and examplesrefer to the nanofiller as supplied including the organic intercalant.

It should be noted that in some instances the word “intercalation”includes the situation when intended to refer to nanofillers which havebeen intercalated with the organic intercalant and the distance betweentheir platelets is increased by a few nanometres are then mixed with(co)polymer(s) and the (co)polymer molecules enter between the nanoplatelet layers thus further intercalating them so that they aredelaminated in the mixing process. This type of further intercalation isherein referred to as “delamination” and/or “furtherintercalation”/delamination/exfoliation. The step of delamination andexfoliation is very important. The effects of this step can be seen inthe changes and improvements in the mechanical and thermo-mechanical andchemical and optical and X-ray diffraction properties of thecompositions.

Nanofillers such as montmorillonite have an anisotropic, plate like,high aspect-ratio morphology which leads to a long and tortuousdiffusion path through the structure of the composition and an improvedbarrier to permeation, particularly when used in combination with thecross-linked ethylene (co)polymers of the present invention.

The amount of nanofiller is about 0.1 to about 15%, preferably about 1to about 10%, more preferably about 2 to about 6% by weight.

It will be appreciated that known fillers may optionally and/oradditionally be included in the composition. Suitable known fillersinclude inorganic and/or mineral fillers such as clays which may becalcined; talc; mica; kaolin; alkaline earth metal carbonates, forexample, calcium carbonate, magnesium calcium carbonate or hydratedbasic magnesium carbonate; and metal hydroxides, for example, aluminumor magnesium hydroxide. The fillers may optionally be coated with, forexample, stearic acid, stearates such as calcium stearate, silanes suchas vinyl silane, siloxanes and/or organo-titanates. While such coatingscan be used to coat the fillers, they can also be added simultaneously,sequentially and/or separately with the fillers.

The composition of the present invention may be subjected to (i) silanegrafting; (ii) the addition of cross-linking agents; and/or (iii)radiation cross-linking at any step of the process.

(i) The silane grafting may be performed using an organic silane and afree radical initiator. In an embodiment preferred for economicalreasons, effective amounts of organic silane and peroxide are added tothe (co)polymer and/or nanofiller either before or during the mixingstep and then grafted onto the (co)polymer at temperatures preferably ofabout 160 to about 240° C., more preferably about 180 to about 230° C.,most preferably about 190 to about 220° C. This grafting is carried outeither in the first mixing step or in a subsequent or even in a separatemixing step, after the (co)polymer and nanofiller have been mixed. In aparticularly preferred embodiment, the silane and the peroxide are addedto both the (co)polymer and/or nanofiller which facilitates exfoliationand/or delamination of the nanofiller and grafting to the polymer in onestep. In an alternative embodiment, the (co)polymer is grafted using theorganic silane and peroxide and then mixed with the nanofiller followedby exfoliation and/or delamination.

In another embodiment, the (co)polymer(s), of which at least one haspolar group(s), is or are mixed with the nanofiller for the purpose ofpolymer intercalation and/or delamination or exfoliation at temperaturesup to about 200° C. The resulting intercalated polymer is then mixed ina second step with further (co)polymer, a free radical initiatorperoxide and an organic silane and grafted onto the (co)polymer(s) athigher temperatures, preferably about 190 to about 220° C. Themasterbatch of nanofiller in a (co)polymer(s) can be made with about 15to about 45% nanofiller content. It is then subsequently mixed in asecond step with further (co)polymer(s) and then grafted with peroxideand vinyl silane in the same second step or in a third step.

Suitable organic silanes include vinyl silanes, for example, vinylalkoxy silane such as vinyl-tris-methoxy-silane (VTMOS),vinyl-tris-methoxy-ethoxy-silane (VTMOEOS), vinyl-tris-ethoxy-silane,vinyl-methyl-dimethoxy-silane andgamma-methacryl-oxypropyl-tris-methoxy-silane; or long aliphatichydrocarbon chain silanes.

Vinyl silanes are preferred and may be added in an amount from about 0.5to about 2.2% by weight of the (co)polymer, preferably about 0.8 toabout 2%, more preferably about 1 to about 1.8% by weight.

The term “free radical initiator” is used herein in its broadest senseand refers to an unstable molecule or compound which generates freeradicals. Examples of suitable initiators include peroxides such asdicumyl peroxide, di-tertiary-butyl peroxide, tertiary-butyl-cumylperoxide and bis-tertiary-butyl-cumyl peroxide i.e.,di(tert-butyl-peroxy-diisopropyl benzene) and2,5-dimethyl-2,5-di(tert-butylperoxy)hexane. The free radical initiatoris preferably added in an amount of about 0.05 to about 0.3% by weightcalculated on the amount of (co)polymer, more preferably about 0.15 toabout 0.2% by weight. The (co)polymer and/or composition may also becross-linked after grafting the (co)polymer or composition with anorganic silane with the aid of a free radical initiator. Catalysts forcross-linking include DBTDL (di-butyl-tin-dilaurate) ordioctyl-tin-dilaurate (DOTDL) or other known catalysts. For this type ofsubsequent cross-linking the presence of moisture, water or steam isrequired, preferably with a catalyst added. A wider, more flexible rangeof ratios of peroxide to vinylsilane to be grafted is possible. Theperoxide addition is possible up to about 0.5%.

Silane cross-linking is also called moisture cross-linking. Afterforming the article made by extrusion and/or moulding, film forming iscarried out in the presence of water, steam or moisture at ambient orpreferably at higher temperatures of up to about 90° C. to about 100° C.or higher if pressure is applied. Catalyst e.g. di-butyl-tin dilaurate(DBTDL), di-octyl-tin dilaurate (DOTDL), is added to the cross-linkablecomposition prior to or during forming, or it can be added to the waterused for cross-linking in it as a medium.

The speed and the duration of the cross-linking will depend on the typeof (co)polymer and nanofiller used in the composition, of thetemperature, of the humidity or water present and of the thickness ofthe composition.

(ii) The (co)polymers, compositions and/or articles of the presentinvention may be cross-linked by adding cross-linking agents such asorganic peroxides, for example, dicumylperoxide, di-tert-butyl peroxide,and/or di-tert-butyl cumyl peroxide preferably in amounts of about 1.4to about 2.2% by weight. These agents are added to the (co)polymer andnanofiller either by absorption at temperatures where they are or becomeliquid (e.g. at about 60° C.), or in a subsequent melting process in amixer keeping the temperature of the melt below the decompositiontemperature of the peroxide(s) i.e., below about 120° C. Silanes are notrequired in this process for grafting, however they may be added or havebeen added separately to the filler(s) or added in the mixing processprior to or during the mixing of the peroxide to the (co)polymer andnanofiller mix preferably keeping below about 120° C. Co-agents such aspolyallylcyanurates (TAC and Sartomer 350) may also be added prior to orduring the mixing of the peroxide(s).

The composition can be cross-linked at temperatures above thedecomposition temperature of the peroxide(s) in the absence of oxygen.The cross-linking of the peroxide cross-linkable composition or theresulting products may be conducted after forming of the article byextrusion and/or moulding, in steam or nitrogen or liquids such asmolten salt mixtures, for example, potassium nitrate-nitrite mixturesunder pressure at elevated temperatures, higher than the decompositiontemperatures of the peroxides used to form free radicals at about 150 toabout 220° C.

(iii) The radiation cross-linking may be conducted usinggamma-radiation, for example, CO⁶⁰ or high energy electron beamradiation in air or under nitrogen at ambient or above ambienttemperatures. Co-agents such as Sartomers, which enhance radiationcross-linking and enable a lower radiation dose to be used, can also beadded either during or subsequent to the mixing step preferably in anamount of about 1 to about 3% by weight. Examples of such co-agentsinclude unsaturated allylic compounds, triallylcyanurate, acryliccompounds and acrylate or polyacrylate compounds. Protection againstradiation damage to the (co)polymer can also be achieved by the additionpreferably of up to about 2% by weight of radiation protectors such astrimethyl quinoline polymers or oligomers, for example, Age Rite Resin Dand Anox HB.

Radiation cross-linking may be carried out at room temperatures orrising above ambient due to the high energy radiation.

It will be appreciated that one or more additives known in the art ofpolymer processing can also be included in the composition and added atany stage of the process. They can be added during the mixing steps orat the stage of forming in the form of masterbatches/concentratesincorporated separately or in the catalyst masterbatch. Suitableadditives include antioxidants, for example, phenolic antioxidants suchas SANTONOX R marketed by Monsanto and IRGANOX 1010 which ispentaerythritol tetrakis (3-(3,5-di-tertbutyl-4-hydroxyphenyl)propionateor IRGANOX 1035 which isoctadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate, IrganoxB900, or process stabilisers such as Irgafos 168 marketed by Ciba-Geigyor aminic antioxidants such as Vulcanox HS and Flectol H which arepolymerised 2,2,4-trimethyl-1,2-dihydroquinoline; metal deactivatorsand/or copper inhibitors, for example, hydrazides such as oxalic acidbenzoyl hydrazide (OABH) or Irganox 1024 which is2,3-bis((3-(3,5-di-tert-butyl-4-hydroxyphenyl)proponyl))propionohydrazide; UV absorbers, for example Tinuvin or HALS type UV absorbers;foaming or blowing agents which may be either endothermic or exothermicfor example, p.p-oxybis benzene-sulfonyl-hydrazide,azo-iso-butyro-nitrile and azodicarbonamide; processing and/or thermalstabilisers, for example tris (2,4-ditert-butylphenyl)phosphite(phosphite based), pentaerythritol tetrakis(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate),octadecyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate,3,3′,3′,5,5′,5′-hexa-tert-butyl-a,a′,a′-(mesitylene-2,4,6-triyl)tri-p-cresol(phenolic based) and dioctadecyl-3,3′-thiodipropionate (thioesterbased); pigments, for example, inorganic pigments such as titaniumdioxide and carbon black and organic pigments; flame retardants, forexample, borates and metaborates such as zinc borate or metaborate,glass beads or particles, silica, silicon dioxide, compounds of silicondioxide with other metal oxides; extenders, plasticisers or softeners,for example, polymeric plasticisers, phthalates such asdioctylphthalate, dioctylsebacate or dioctyladipate or mineral oils suchas naphthenic, paraffinic or aromatic oils.

The (co)polymers are preferably granulated, pelletised, powderised, cutand/or diced. The (co)polymer and the nanofiller can then be premixed oradded simultaneously, sequentially and/or separately to any suitableknown apparatus, such as roll mills, internal mixers, for example, ofthe Banbury or Shaw type, single screw mixers of the Buss-Ko-Kneadertype or continuous mixers, for example, twin screw mixers such ascontra-rotating or co-rotating or co-rotating twin screw mixers i.e.,Werner Pfleiderer ZSK. It will also be understood that the known fillersand/or additives can be added simultaneously, sequentially and/orseparately at any stage of the processing.

The nanofiller or composition may be intercalated with (co)polymer(s),delaminated and/or exfoliated using any suitable known technique such ashigh shear processing, for example, in the mixing apparatus referred toabove. In variations of process steps (a) to (c) defined above, afurther exfoliation and/or delamination step may be performed using themixing apparatus described above.

Similar mixing apparatus may be used for silane grafting (i) describedabove.

For mixing, delaminating, exfoliating and/or silane grafting, thesemixing apparatus may be equipped with nitrogen blanket applicators,pre-dryers, either pre-mixing and/or dosage equipment/pumps for thesilane and peroxide mix, side-feeders, vacuum ports, several entryports, granulation, pelletising and/or dicing equipment.

Mixing is preferably performed in one step, for economical reasons. Itcan also be done in two separate steps.

In one embodiment, the first step involves mixing andintercalation/delamination/exfoliation preferably at temperatures at upto about 200° C. and then separately grafting the silane with peroxidein a second step at temperatures of above about 200° C., but preferablynot higher than about 220° C.

In another embodiment, the (co)polymer(s) are grafted in a first step atabout 200° C. to about 240° C. and then in a second step after cooling,adding the nanofiller either as a masterbatch/concentrate which has beenintercalated with polymer and delaminated/exfoliated and mixing attemperatures of up to about 200° C., or adding the nanofiller(s) to thegrafted (co)polymer and intercalating withpolymer/delaminating/exfoliating the nanofiller at temperatures of up toabout 2002C.

In a further variation of the process of the invention, the (co)polymer,nanofiller and/or other additives are advantageously dry or dried in aseparate step prior to processing involving hot air or dessicated hotair, in particular when silane grafting is used.

The composition of the invention can be formed by any suitable knownprocess including moulding, such as injection moulding, blow moulding orcompression moulding; pressing; vacuum forming; extrusion such as coextrusion, tandem extrusion or lamination with other layers for examplepolymeric layers; calendering and heat shrinking. The heat shrinkingprocess involves cross-linking the article of the composition andheating and stretching the composition and then cooling the compositionin its stretched state. When the heat shrinkable articles are reheatedto temperatures above the crystalline melting point, they display shapememory properties, that is, they retain or regain or shrink to theiroriginal shape and size.

The composition of the present invention is either cross-linkable in theform of granules, premixes or mixes, pellets, tapes or profile orintermediary, semi-fabricated articles or cross-linked in the form ofintermediary, semi-fabricated or final articles. Examples of articlesinclude profiles, tubes, pipes, films, sheet, tiles, floor coverings,containers and packaging for food.

The compositions of the present invention possess advantageousproperties including high modulus and strength, increased barrierproperties such as reduced penetration, permeation and/or lowerdiffusion of chemical solvents, oils and gases, reduced swelling, highheat distortion temperatures, increased dimensional stability, nomelting, improved flame retardancy, lower specific gravity/density.These properties exist and their improvements are more evident inparticular at high temperatures or in adverse environmental conditions.

Examples of applications of the composition include:

Medical: protective gear and clothing, medicine containers, layeredproducts;

Defence applications and work protection: protection against externalchemicals, substances;

Transport: land, vehicles, trains, subways, sea, ships, air, transportof liquids or gases such as pipelines, pipes for hot water underpressure and gas;

Construction: high rise, towers, installations and rooms withelectronics, switches, computers, offices, public areas, theatres,cinemas, malls, stations, airports, telecom installations, storage,pipes and tubes;

Agriculture;

Food: packaging of consumables, protecting food in laminated films; and

Packaging: of chemicals, paints, liquids, solutions, dispersions,aqueous or solvent based.

EXAMPLES

The invention will now be described with reference to the followingnon-limiting examples.

The compositions of the examples were prepared using various continuousco-rotating twin-screw mixers of ZSK type from Werner & Pfleiderer ZSKand/or Toshiba TEM, of different sizes and build. The compositions ofComparative Examples 1 and 2 and Examples 1 to 3 were prepared on aZSK53 line A with the co-rotating screws of 53 mm diameter each withscrew speeds of around about 200 rpm and feeding of about 50 kg/hour.The compositions of Examples 4 to 6 were prepared on a ZSK120 withco-rotating screws of 123 mm diameter with down stream feeders (lineD),using a range of around 150 to 180 rpm and a feeding rate of up to about400 kg/hour.

The compositions of Examples 9 to 24 were mixed on a ZSK (line A) with53 mm screw diameters (same as for Examples 1 to 3), unless indicatedotherwise, namely: Examples 7 to 9, 12 to 22 were made on line A. Thescrew speeds were however in the range of 180 to 200 and in someexamples even to 250 rpm as it was found that exfoliation was improvedat higher speeds.

The compositions of Examples 11 and 12, (similar to Examples 4 to 6)were prepared on a TEM 120 mm line with screw diameters of 123 mm withdown stream feeders. Various screw speeds and temperature ranges wereused, adequate to the task and (co)polymer(s) and type ofperoxide-silane mixes used in case of grafting or a grafting step. Thescrew speeds were varied and used up to 250 rpm such as in Example 15.

The temperature was in the general range of 180-220° C. for LLDPE and190-240° C. for HDPE.

The temperatures were in a number of Examples kept below about 200° C.on the extruder zones and 210° C. melt temperature at the exit tominimise degradation effects on the and to protect the intercalatingagent in the nanofiller; in case of grafting the temperatures were at oraround 190° C. preferably 200 to 210° C. in the extruder zones and 210°C. to about 220° C. or more at the exit melt temperatures or higher, inparticular when the grafting was performed in a second step.

In Comparative Examples 1 and 2 and Examples 1, 2, 5 and 7, thecomponents were mixed and grafted in the first step and either nonanofiller was added or nanofiller was added in the same step (Examples1 and 2), or later (Example 8). Examples 8 and 9 were made usingcompositions premixed with nanofillers from Examples 7 and 4 and otherPE additives followed by grafting with peroxide and silane in a secondstep.

In Examples 12, 13 and 14, the components were mixed, grafted andfurther intercalated with polymer and/or exfoliated in one step, withthe addition of some components.

In Examples 3, 4, 6, 10, 11, 15A, 15B, 17, 19A, 20A and 21 thecomponents were mixed with nanofillers and the (co)polymer(s) processingthem for further intercalation (with the polymer and/or co-polymer) andfor exfoliation in a first step and these compositions were thenavailable for use as such or mixed with additional (co)polymer(s) andwith vinylsilane and peroxide for grafting in a second step.

Examples 16, 18, 19B and 22 were prepared using compositions fromExamples 15A, 17, 19A and 20 respectively which were prepared in aseparate first step in which the nanofiller was added and furtherintercalated/exfoliated and then in the second step, grafting withvinylsilane and peroxide and further exfoliation was performed.

Example 21 was also made in a second step using the masterbatchcomposition from example 20 added to additional PE polymers with furtherexfoliation. Example 21 can be used as such and is cross-linkable whengrafted with peroxide and siloxane in the same second step or in aseparate third step.

Some of the additives and nanofillers were added as pre-mixed or as amaster-batch or concentrate. This was also the case in the exampleswhere the compositions from previous examples were used in a secondstep.

In some of the examples, the nanofiller was mixed with a polar(co)polymer(s) and intercalated/exfoliated in a first step forming apre-mix or masterbatch or concentrate and then mixed with more or added(co)polymer(s) with silane grafting and furtherintercalation/exfoliation in a second step.

A nitrogen blanket was used in each example (i.e. the feeding zone orzones were under nitrogen atmosphere for safety reasons and also formore efficient use of the peroxide radical initiator).

The processing was done as far as possible under dry conditions.

The compositions were granulated or pelletised directly at the exit ofthe ZSK mixers. Packaging was in metal lined bags of various size.

The silane grafted material was mixed with 4% of a catalyst masterbatchof e.g. DLDTP which is an accelerator catalyst directly prior to theformation of a product e.g. extrusion forming to tapes or to injectionmoulding for test plaques or prior to extrusion or extrusion of largeritems or blow forming. These were then cross-linked in hot water, attemperatures of 90 to 110° C. for 1 to 2 up to 4 hours, depending of thethickness of the sample.

The testing was performed to Australian Standards (AS) which are ingeneral harmonised with International Standards such as IEC, BS,DIN/VDE, EN (European Norms) and to ASTM test methods.

Mechanical properties were tested to above standards.

Oil resistance (O.R.) was tested to ASTM using ASTM oil nr.2, acriterion is the retention of 70% of original properties.

Environmental stress crack resistance (ESCR) was also tested to ASTM(AS)in tensioactive liquid at 50° C., with unnotched samples. Ingeneral, results of over 100 hours are aimed to be achieved. In the caseof nanocomposites and in particular cross-linked nanocomposites, resultsof thousands of hours e.g. 8000 hours were achieved and are stillongoing.

Hot Set test (HST) was made to AS: non-cross-linked materials, includingnanocomposites would fail the test at above their melting temperaturesand break away after short time anyway at 200° C. The requirement forcables is a maximum elongation under load of 175%. After 20 minutes andtaking the load away the samples must revert to a maximal residualelongation of 15% or 25% for rubber/elastomers.

For some other applications the requirements are not so restricted.

The elongations under load could be higher.

The cross-linked or cross-linkable compositions of the present inventionpass the HST.

Gel content was performed in boiling xylene to ASTM. The gel contentshows that a composition has some degree of cross-linking. The main testfor cross-linking is the HST. The gel content in silane graftedcross-linked materials is less related to the HST.

Impact resistance is tested to ASTM D-256 Izod pendulum impactresistance of notched plastics.

The components used in the examples are from:

Qenos, Melbourne, Australia: for HDPE GM7655, GA7260H, HD1090, HD6025,LLDPE Alkatuff 425;

BASF Ludwigshafen, Germany: for HDPE HMW Lupolen 4261A;

Sabic, LLDPE Ladene MG200024;

DuPont, USA: EVA Elvax 470, Elvax 750, Elvax 760, MAH-HDPE FusabondMB100D;

Sud-Chemie, Moosburg, Germany: Nanofil 15, Tixogel MP100;

SCP Southern Clay Products, Gonzales, Tex., USA: Cloisite 15A, Cloisite20A;

Crompton, USA/Switzerland: Silox VS 911, Silox VS924, Peroxide andSilane mix.

Other suppliers of similar materials e.g. Degussa, Germany, etc. CIBA,Switzerland: Antioxidants, Stabilisers: Irgafos FF168, Irganox B900;

Great Lakes Chemicals, USA: Antioxidants: Anox 20.

Compco Pty Ltd, Melbourne, Australia: Compylene Master-batches ofAntioxidant: EL900140AO, Processing aid: FL90016PA5.

The proportions of the components used in the compositions of theExamples are given in % by weight of the total composition. These %shave been rounded to the first decimal point.

Comparative Example 1

HDPE Qenos GM7655 MFI 0.2, granules 83.5% HDPE Qenos GA7260H MFI 25,powder 14.7% Silox VS 911 Crompton 1.2% Stabiliser Irganox 168 FF 0.2%Anox 20 Great Lakes 0.4%

Hot Set Test (at 200° C.): Elongation under load 37% Residual elongationrelaxed, no load  0%

Comparative Example 2

LLDPE Alkatuff 425 (MFI 2.5) granules 78.7% LLDPE Ladene MG200024, (MFI20)powder 19.7% Silox VS 924 (Vinyl silane and Peroxide) 1.4% Irganox B900 0.2%

Hot Set Test (at 200° C.):

with load 270%* without load 10%*requires more Silox addition to 1.6%

Example 1

LLDPE Alkatuff 425 granules 73.8% LLDPE Ladene GM200024, powder 18.4%Silox VS 924 1.6% MAH-HDPE Fusabond MB 100D 1.0% Irganox B 900 0.2%Tixogel MP 100 Sudchemie 5.0%

Hot Set Test (at 200° C.): under load 77% without load  0%

Example 2

LLDPE Alkatuff 425 granules  74% LLDPE Ladene powder 18.5%  Silox VS 9241.4% MAH-HDPE Fusabond MB 100 D 1.0% Antioxidant Irganox B 900 0.1%Tixogel MP 100 filler 5.0%

Hot Set Test (at 200° C.): under load 100% without load  0%

The addition of Tixogel has significantly improved the cross-linking ofthe composition compared to Example 2.

Example 3

LLDPE Alkatuff 425 granules 79.3% LLDPE Ladene powder 14.0% MAH-HDPEFusabond MB 100 D  1.0% Irganox 168 FF  0.2% Anox 20  0.4% Tixogel MP100  5.1% Flexural modulus, Mpa 557     Tensile Strength (TS), at yieldMpa 24.2    Tensile strength at break Mpa 13.2    Impact resistanceIzod, Mpa 273    

This composition is not grafted nor cross-linked.

Example 4

HDPE HMW Lupolen 4261A powder 88.1%  Stabiliser mix: Irgafos 168FF +Anox20 + Ca-Stearate (0.2 + 0.2 + 0.5%) 0.9% MAH-HDPE Fusabond MB 100D1.0% Tixogel/Lupolen mix (30% Tixogel:70% Lupolen): Lupolen 4261A 7.0%Tixogel MP100 (via side feeder) 3.0% Flexural modulus, Mpa 531     TS atyield Mpa 22.1    TS at break Mpa 17.3    Elongation at break  568% Impact resistance Izod, J/m 156    

This composition is made in one step and is not grafted norcross-linked.

Example 5

HDPE GM 7655 granules 82.0% Lupolen 4261 powder*(pre-mixed withfollowing Silox) 13.4% Silox VS 911*(pre-mixed with above Lupolenpowder) 1.6% Processing aid Compylene FL900140AO 1.0%(Masterbatch/concentrate: 5% Fluorocarbon polymer in 90% LLDPE)Stabiliser/Antioxidant masterbatch EL900140AO 2.0% (10% Irganox B900 and90% LLDPE)The Pre-mix* of Lupolen and Silox was high speed pre-mixed and added viaa separate feeder.

Hot Set Test (at 200° C.): Elongation with load    160% Elongationrelaxed (after removing load)     7% Flexural modulus, Mpa 558 TS (atyield, Mpa  23 TS at break, Mpa   14.8 Impact resistance Izod, J/m 771

Example 6 Composition from Example 5 [90%]

HDPE GM 7655 granules* 73.0%  HDPE GA 7260H powder* 11.9%  Silox VS 911*1.4% Antioxidant* (masterbatch/concentrate) 1.8% Process aid*(masterbatch/concentrate) 0.9% MAH-HDPE Fusabond 100 D 1.0% [Subtotal ofgrafted composition* ex. 5  90%

Composite mix**(incl. Tixogel filler) [10%] Tixogel MP 100(via sidefeeder) 3.0% Irgafos 168FF(process stabiliser) 0.2% Calcium stearate0.5% HDPE, MFI 20, MG 20224 powder 0.9% HDPE Lupolen 4261A 2.1%Composition of Example 5 3.1% Anox 20 0.2% Subtotal of composite mix**10.0%  Total composition example 6  100% *These components were pre-mixed and grafted separately.

Hot Set Test (at 200° C.): (above 10% comp. mix** consisting of:elongation under load 173% elongation with load removed (relaxed)  7%

Example 7

HDPE MFI 10, HD1090 granules 88.3% LLDPE Ladene MG200024 powder 9.7%Silox VS 911 1.6% Irgafos 168 FF (process stabiliser) 0.2% Anox 20 0.2%After grafting and just prior to forming, 5% catalystmasterbatch/concentrate was added.

Hot Set Test (at 200° C.): Elongation under load 250% Residualelongation relaxed  16% Flexural modulus, Mpa 552 TS at yield Mpa   24.2TS at break Mpa   15.5 Gel content (BS EN579, after boiling in 54.7% xylene): O.R. (Oil Resistance ASTM Oil nr. 2 100° C., 24 hrs):O.R.TS(yield) retained: 82.1%; TS(break)retained: 143% O.R. EB(elongation at break) change: +133%   O.R.: change in dimensions:  +4%   Impact resistance Izod, J/m 686 ESCR (ASTM) F0, hours(environmental stress crack 8820  resistance, at 50° C. No failure after8820 hours, ongoing)

Example 8

Composition of Example 7 86.9% HDPE Ladene GM200024 (MFI 20)powder 8.7%Tixogel MP100 3.0% Stabiliser mix composed of: Irgatos 168FF (processstabiliser) 0.2% Anox 20 antioxidant 0.2% MAH-HDPE Fusabond MB100D 1.0%

Hot Set Test (at 200° C.): load 167% relaxed  13% TS at yield, Mpa  25.6 TS at break, Mpa   16.5 Flexural modulus, Mpa 655 Gel content (BSEN 579) 55.8%  O.R. (oil resistance ASTM Oil nr. 2, 100° C., 24 hrs):O.R. TS(yield) retained: 82.5%; TS(@break)ret 131% O.R. EB(elong. @break) +105%   change: O.R. change in dimensions  3.5%  Impactresistance Izod, J/m 221 ESCR, F0(no failure, ongoing)hrs 8820 

Example 9

Composition of Example 4 88% HDPE GM5010T2 powder 10% Antioxidant 0.4% Silox VS 911 1.6%  HST (Hot Set Test 200° C., 200 kPa): 63%

Example 10

HDPE 1090 53% GM 7655 powder 15% MAH-HDPE Fusabond MB100D 15% Nanofil 15(via side feeder) 15% Antioxidant EL900140(10% Irganox B900, 90% LLDPE) 2% TS at yield, Mpa 28.5 TS at break, Mpa 11.6 Flexural modulus, Mpa912   Impact resistance Izod, J/m 155  

This composition is not-grafted nor cross-linked. It can be silanegrafted and cross-linked or added as a masterbatch to other compositionsto have a Nanofil concentration of 5 or 3% and to be grafted andcross-linked.

Example 11

HDPE GF 7655 83%  HDPE GM 7655 powder 5% MAH-HDPE Fusabond MB100D 5%Antioxidant EL900140(10% Irganox B900, 2% 90% LLDPE) Cloisite 20A* (viaside feeder) *5%  Nanofil 15 (via side feeder) 5% TS at yield, Mpa 26.9*29.2 TS at break, Mpa 11.5 11.5 Flexural modulus, Mpa 757 851   Impactresistance Izod, J/,m 161 193  

This composition may be grafted with vinylsilane and peroxide forsubsequent cross-linking. Alternatively, the composition may becross-linked after peroxide addition or by other cross-linking.

Example 12

EVA Elvax 760 (9.3% VA, MFI2 = 2) 83.2 LLDPE Ladene MG200024 (20MFI)powder 10 Nanofil 15  5% Silox VS 924 1.8%  HST: 50%

Example 13

MAH-HDPE Fusabond MB100D 83.2% LLDPE Ladene MG200024 (MFI20)   10%Nanofil 15   5% Silox VS 924  1.8% TS at yield, Mpa 25.2 TS at break,Mpa 15.0 Flexural modulus, Mpa 654   O.R. (oil resistance), TS @ breakretained:   99% O.R. EB (elongation @ break) retained   95% Gel content:28.8% Impact resistance Izod, J/m 103  

Example 14

MAH-HDPE Fusabond MB100D 83.2% LLDPE Ladene MG200024 (MFI20)   10%Nanofil 15 (dried)   5% Silox VS 924  1.8% TS at yield, Mpa 25.0 TS atbreak, Mpa 15.2 Flexural modulus, Mpa 636   Gel content:   34% O.R.(100° C., 24 hrs), TS @yield retained:   80% O.R. 100° C., 24 hrs TS @break retained:   95% O.R. (100° C., 24 hrs), EB retained: 90.5% Impactresistance Izod, J/m 114  

Example 15

Elvax 750 EVA (9% VA, MFI2 = 7) 70% LLDPE Ladene MG200024 (MFI20) 15%Nanofil 15 15%

This composition is not grafted nor cross-linked. Examples: Ex. 15A Ex.15B Mixed at rpm: 200 rpm 250 rpm HDT(° C.) 36 35 TS at yield, Mpa 8.28.3 TS at break, Mpa 8.4 8.5 Elongation at break, % 110 107 Flexuralmodulus, Mpa 222 242[Note:increase in flexural modulus with increase in rpm]

Example 16

HDPE Qenos GF 7660 54.9% LLDPE GME200024 powder   10% Composition ofExample 15A 33.3% Silox VS 911  1.8% HST (hot set test at 200° C.):  23%

Example 17

EVA Elvax 470(18% VA, MFI2 = 0.7) 70% LLDPE Ladene MG200024 (20MFI)powder 15% Nanofil 15 15%

This composition is not grafted nor cross-linked. HDT: ° C. 41 TS atyield, Mpa 7.9 TS at break, Mpa 12.6 Elongation at break, % 420 Flexuralmodulus, Mpa 851

Example 18

HDPE GF 7660 54.9% LLDPE GM200024 powder   10% Composition of Example 1733.3% Silox VS 911  1.8% TS at yield, Mpa 24.7 TS at break, Mpa 22.0 HST(at 200° C., 200 kPa):   20% Gel content (BS EN 579, boiling xylene):67.1% O.R.: TS @ break retained:   95% O.R. EB retained:  115% Impactresistance Izod, J/m 560  

Example 19

Example 19A MAH-HDPE Fusabond MB100D 70% LLDPE Ladene MG200024 (MFI 20)15% Tixogel MP100 15%

The components were mixed in one step. This composition is not graftednor cross-linked.

Example 19B

HDPE Qenos GF 7660 54.9% LLDPE Ladene GM200024 powder   10% Compositionof Example 19A 33.3% Silox VS 911  1.8% TS at yield, Mpa 30.7 TS atbreak, Mpa 26.0 Flexural modulus, Mpa 744   HST: (excellent)   27% Gelcontent 55.3% O.R. TS @break retained:  104% O.R. EB (elong. at break)retained:  154% O.R. change. +54% O.R. change in dimensions: 3% resp. 5%

Example 20

MAH-HDPE Fusabond MB100D 70% LLDPE Ladene MG200024 (MFI = 20) 15%Nanofil 15 15%

This composition is not grafted nor cross-linked.

Example 21

HDPE GF7660 56.7% LLDPE GM200024 powder   10% Composition of Example 2033.3%

This composition is not grafted nor cross-linked. The Nanofil 15 contentafter the composition from Example 20 is mixed with the other componentsis 5%. Flexural modulus, Mpa 839 TS at yield, Mpa 27.7 TS at break, Mpa12.4 Impact resistance Izod, J/m 100

Example 22

HDPE GF 7660 54.9% LLDPE GM200024 powder   10% Composition of Example 2033.3% Silox VS 911  1.8% HST:   40%

Example 23

EVA Elvax 750 (VA 9%, MFI2 = 7) 66.7% Composition of Example 15A,granules 33.3% (mixed granules, by injection moulding) TS at break, Mpa8.2 Elongation at break, % 140  

This composition is not grafted nor cross-linked.

Example 24

EVA Elvax 470 (VA 18%, MFI2 = 0.7%) 66.7% Composition of Example 1733.3% (mixed granules, by injection moulding) TS at break, Mpa 10.9Elongation at break, % 359  

This composition is not grafted nor cross-linked. HDPE 1090 83%  HDPE GM7655 powder 5% MAH-HDPE Fusabond MB100D 5% Nanofil 15 5% AntioxidantEL-900140 2% TS at yield, Mpa 29.2 TS at break, Mpa (inj. mouldeddumbells) 11.2

Many modifications may be made to the preferred embodiment as describedabove without departing from the spirit and scope of the presentinvention.

1. A cross-linkable and/or cross-linked nanofiller composition whichcomprises a cross-linkable and/or cross-linked ethylene (co)polymer andan intercalated nanofiller.
 2. A composition according to claim 1, inwhich the ethylene (co)polymer is selected from polyethylene andethylene based alkene or alphaolefin copolymers.
 3. A compositionaccording to claim 1, in which the ethylene (co)polymer is high densitypolyethylene (HDPE), medium density polyethylene (MDPE), linear lowdensity polyethylene (LLDPE), low density polyethylene (LDPE), very lowdensity polyethylene (VLDPE), ultra low density polyethylene (ULDPE), anethylene hexene copolymer, an ethylene octene copolymer, a butylene(co)polymer, an ethylene-propylene copolymer (EPM), anethylene-propylene-diene terpolymer (EPDM), an ethylene-butylenecopolymer (EBM) or terpolymer (EBDM), an ethylene-vinylsilane(co)polymer, a copolymer or terpolymer of ethylene with acrylic acid(EA) or ethylene with ethylene acrylate and acrylic acid (EAA) ormethacrylic acid (EMA) and/or a copolymer of ethylene with ethylacrylate(EEA), butyl-acrylate (EBA) or vinyl acetate (EVA).
 4. A compositionaccording to claim 3, in which the butylene (co)polymer is polybutyleneor polyisobutylene.
 5. A composition according to claim 1, in which theethylene (co)polymer is in the form of a metallocene catalyst ethylene(co)polymer.
 6. A composition according to any claim 1, in which theethylene (co)polymer or part thereof is grafted with compoundscontaining carboxylic acid or anhydride group(s).
 7. A compositionaccording to claim 6, in which the carboxylic acid or anhydride group ismaleic anhydride or acid or fumaric anhydride or acid.
 8. A compositionaccording to claim 6, in which the grafted ethylene (co)polymer is amaleic anhydride (MAH) or maleic acid grafted copolymer.
 9. Acomposition according to claim 8, in which the maleic anhydride (MAH) ormaleic acid grafted copolymer is LDPE-MAH, LLDPE, HDPE-MAH, EP-MAH,EPR-MAH, PE-MAH or PP-MAH.
 10. A composition according to claim 1, inwhich the ethylene (co)polymer contains polar group(s).
 11. Acomposition according to claim 10, in which the polar group(s) arecarboxylic group(s), maleic group(s) and/or ester group(s).
 12. Acomposition according to claim 10, in which the amount of (co)polymerwith polar group(s) is about 0.01% of the total (co)polymer. 13-14.(canceled)
 15. A composition according to claim 10, in which the amountof (co)polymer with polar group(s) is at least about 8% of the total(co)polymer.
 16. A composition according to claim 3, in which theethylene content of the ethylene-propylene copolymer is about 10 toabout 99.9% by weight.
 17. (canceled)
 18. A composition according toclaim 3, in which the ethylene content of the ethylene-propylenecopolymer is about 75 to about 99.9% by weight.
 19. A compositionaccording to claim 3, in which the vinyl acetate content of theethylene-vinyl acetate copolymer (EVA) is about 3 to about 80% byweight.
 20. (canceled)
 21. A composition according to claim 1, in whichthe ethylene (co)polymer is a plastomer or an elastomer.
 22. Acomposition according to claim 21, in which at least about 40% to about50% by weight of the total weight of (co)polymer is a plastomer with thebalance being an elastomer.
 23. (canceled)
 24. A composition accordingto claim 21, in which the plastomer is HDPE, MDPE, LDPE, LLDPE, VLDPE,EVA with up to about 30% vinyl acetate, EPM with up to about 25%propylene and/or an ethylene octene copolymer with S.G. of at leastabout 0.887.
 25. A composition according to any claim 21, in which theelastomer is an ethylene octane copolymer with a S.G. of up to about0.887, an ethylene hexene copolymer, ULDPE, ethylene propylenecopolymer, an ethylene vinyl acetate copolymer with greater than about38% vinyl acetate, EPDM, EPM, and/or EPR.
 26. A composition according toclaim 25, in which the ethylene propylene copolymer is a terpolymer witha propylene comonomer of greater than about 30%.
 27. A compositionaccording to claim 25, in which the vinyl acetate content forplastomeric EVA is about 9 to about 30% by weight.
 28. A compositionaccording to claim 25, in which the vinyl acetate content forelastomeric EVA is about 38 to about 50% by weight.
 29. A compositionaccording to claim 1, in which the cross-linkable and/or cross-linkedethylene (co)polymer forms at least about 40% by weight of the totalweight of (co)polymer.
 30. A composition according to claim 1, in whichthe nanofiller has particle(s) in the order of size of less than 50 nm.31. A composition according to claim 1, in which the thickness of thenanofiller particles is about 1 nm to about 100 nm.
 32. A compositionaccording to claim 1, in which the diameter or length or width of thenanofiller is up to about 500 nm.
 33. A composition according to claim1, in which the layers of the nanofiller are composed of silicate.
 34. Acomposition according to claim 1, in which the nanofiller isintercalated with an organic intercalatent.
 35. A composition accordingto claim 34, in which the organic intercalatent is an ionic or polarcompound(s).
 36. A composition according to claim 35, in which the ionicor polar compound(s) is a quaternary ammonium salt.
 37. A compositionaccording to claim 36, in which the quaternary ammonium salt is anoptionally substituted long chain hydrocarbon quaternary ammonium salt.38. A composition according to claim 37, in which the optionallysubstituted long chain hydrocarbon quaternary ammonium salt is a benzylor alkyl substituted long chain hydrocarbon quaternary ammonium salt, analkyl substituted tallow or hydrogenated tallow quaternary ammonium saltand/or a bis-hydroxyethyl quaternary ammonium salt.
 39. A compositionaccording to claim 36, in which the counter anion for the quaternaryammonium cation is a halide or methyl sulphate.
 40. A compositionaccording to claim 1, in which the nanofiller is an intercalated mineralnanofiller or clay which is either synthetic or natural and has beenintercalated by organic modification with ionic or polar substances. 41.A composition according to claim 40, in which the mineral or clay ismontmorillonite, bentonite, smectite and/or phyllosilicate.
 42. Acomposition according to claim 40, in which the nanofiller is Cloisite,Nanofil, Tixogel or Kunipia.
 43. A composition according to claim 1, inwhich the amount of nanofiller is about 0.1 to about 15% by weigh. 44.(canceled)
 45. A composition according to claim 43, in which the amountof nanofiller is about 2 to about 6% by weight.
 46. A compositionaccording to claim 35, in which the amount of organic intercalatent isup to about 40% by weight of the nanofiller.
 47. A composition accordingto claim 1, further comprising a second filler.
 48. A compositionaccording to claim 47, in which the second filler is an inorganic and/ormineral filler.
 49. A composition according to claim 47, in which thesecond filler is an optionally calcined clay, talc, mica, kaolin,alkaline earth metal carbonate, and/or metal hydroxide.
 50. Acomposition according to claim 49, in which the alkaline earth metalcarbonate is calcium carbonate, magnesium calcium carbonate and/orhydrated basic magnesium carbonate.
 51. A composition according to claim49, in which the metal hydroxide is aluminum and/or magnesium hydroxide.52. A composition according to claim 47, in which the second filler iscoated.
 53. A composition according to claim 52, in which the secondfiller is coated with stearic acid, stearate, silane, siloxane and/ortitanate.
 54. A composition according to claim 1, further comprising anorganic silane grafted to the ethylene (co)polymer and/or intercalatedinto the nanofiller.
 55. A composition according to claim 54, in whichthe organic silane is a vinyl silane and/or a long aliphatic hydrocarbonchain silane.
 56. A composition according to claim 55, in which thevinyl silane is a vinyl alkoxy silane.
 57. A composition according toclaim 56, in which the vinyl alkoxy silane is vinyl-tris-methoxy-silane(VTMOS), vinyl-tris-methoxy-ethoxy-silane(VTMEOS),vinyl-tris-ethoxy-silane, vinyl-methyl-dimethoxy-silane and/orgama-methacryl-oxypropyl-tris-methoxy-silane.
 58. A compositionaccording to claim 55, in which the vinyl silane is added in an amountfrom about 0.5 to about 2% by weight.
 59. (canceled)
 60. A compositionaccording to claim 58, in which the vinyl silane is added in an amountof about 1% to about 1.8% by weight.
 61. A composition according toclaim 54, in which the organic silane is grafted using a free radicalinitiator.
 62. A composition according to claim 61, in which the freeradical initiator is a peroxide.
 63. A composition according to claim62, in which the peroxide is dicumyl peroxide, di-tertiary-butylperoxide, di-tertiary-butyl-cumyl peroxide and/orbis-tertiary-butyl-cumyl peroxide.
 64. A composition according to claim61, in which the free radical initiator is added in an amount of about0.05 to about 0.3% by weight.
 65. (canceled)
 66. A composition accordingto claim 1, in which the composition and/or ethylene (co)polymer aresilane cross-linked, cross-linked by adding a cross-linking catalyst orradiation cross-linked.
 67. A composition according to claim 1, furthercomprising one or more polymer processing additives.
 68. A compositionaccording to claim 67, in which the additive is an antioxidant, metaldeactivator, copper inhibitor, UV absorber, foaming or blowing agentwhich is either endothermic or exothermic, processing and/or thermalstabiliser, pigment, flame retardant, extender, plasticiser and/orsoftener.
 69. A process for preparing a cross-linkable and/orcross-linked nanofiller composition which comprises either: (a) mixingand delaminating and/or exfoliating in one step a cross-linkable and/orcross-linked ethylene (co)polymer and an intercalated nanofiller; (b)mixing a cross-linkable ethylene (co)polymer with an intercalatednanofiller; and delaminating and/or exfoliating at least part of thenanofiller; or (c) delaminating and/or exfoliating at least part of anintercalated nanofiller; and mixing the delaminated and/or exfoliatedintercalated nanofiller with a cross linkable and/or cross-linkedethylene (co)polymer.
 70. A process according to claim 69, in which theethylene (co)polymer and/or nanofiller are subjected to grafting eitherbefore, during or after the mixing and/or exfoliating and/ordelaminating step(s).
 71. A process according to claim 70, in which thegrafting involves treating the ethylene (co)polymer and/or nanofillerwith an organic silane which is then grafted onto the (co)polymer and/orintercalated into the nanofiller.
 72. A process according to claim 71,in which the organic silane is grafted using a free radical initiator.73. A process according to any claim 69, further comprising the step ofcross-linking the (co)polymer after step (a) or cross-linking thecomposition after step (b) or (c).
 74. A process according to claim 73,in which the composition and/or ethylene (co)polymer is silanecross-linked, cross-linked by adding a peroxide cross-linking catalyst,silane cross-linked or radiation cross-linked.
 75. A process accordingto claim 69, in which the (co)polymer is granulated, pelletised,powderised, cut and/or diced.
 76. A process according to claim 69, inwhich the (co)polymer and the nanofiller are premixed or addedsimultaneously, sequentially and/or separately to a mixing apparatus.77. A process according to claim 69, in which the nanofiller orcomposition are exfoliated and/or delaminated using high shearprocessing.
 78. A process according to claim 69, in which a furtherexfoliation and/or delamination step is performed at any stage of theprocess.
 79. A process according to claim 69, in which other fillersand/or additives are added simultaneously, sequentially and/orseparately at any step of the process.
 80. A process according to claim79, in which the (co)polymer, nanofiller, other fillers and/or additivesare dry or dried in a separate step prior to step (a).
 81. An articlewhich is wholly or partly composed of the nanofiller composition definedin claim
 1. 82. An article according to claim 81, which is a profile,tube, pipe, film, sheet, tile, floor covering, container or packagingfor food.
 83. A process for preparing the article defined in claim 81,which comprises a step selected from the group consisting of either: (a)forming or shaping the nanofiller composition defined in claim 1; (b)combining at least one layer of the nanofiller composition defined inclaim 1 with at least one other polymeric layer; (c) cross-linking thenanofiller composition defined in claim 1; and (d) heating andstretching the nanofiller composition defined in claim 1 and cooling thestretched composition.